1. Technical Field:
This invention relates to a method and apparatus for pouring and stirring molten metal into a receiving vessel in a neutral atmosphere.
2. Description of Prior Art:
Prior Art devices of this type have generally been directed to shroud systems and stirring lances that inert gas or oxygen to the molten metal to form either shroud seals as seen in U.S. Pats. No. 4,429,816, U.S. Pat. No. 3,460,725, U.S. Pat. No. 455,050 and applicant's U.S. Pat. No. 4,624,292 or stirring lances see for example U.S. Pats. No. 4,619,443 or applicant's U.S. Pat. No. 4,740,241.
In U.S. Pat. No. 4,429,816 a union for providing inert gas is disclosed that utilizes a union block between a pouring nozzle and a pouring tube. The union block has a metal jacket surrounding same for the inclusion of inert gas under pressure to form a seal and a protective gas film within the pouring tube.
U.S. Pat. No. 3,460,725 discloses a two-part refractory shroud tube into which inert gas can be added under pressure.
U.S. Pat. No. 4,555,050 shows a closure mechanism with a gas seal for discharged nozzles on a metallurgical vessel. A snug conical joint is formed between the discharge nozzle and a shielded tube. An annular surface is formed defining a ring shaped seal that is filled with inert gas.
In applicant's U.S. Pat. No. 4,624,292 a method and apparatus is disclosed that uses a closure within the vessel through which a pouring nozzle extends. Inert gas is supplied through the closure in spaced relation to the nozzle engagement forming a neutral inert gas atmosphere within the vessel and around the nozzle.
U.S. Pat. No. 4,740,241 and applicant's U.S. Pat. No. 4,619,443 shows examples of stirring lance configurations that can be used in metallurgical vessels. Each has a cast or coalesce refractory body through which gas tubes extend and exit therefrom.